Objective. To identify and determine the phytoconstituent structure of Tessaria integrifolia Ruiz & Pav. leaves with leishmanicidal activity. Materials and Methods. Fluid extract of leaves was prepared, concentrated to soft extract, and used to evaluate leishmanicidal activity in Mesocricetus auratus with experimental leishmaniasis, at the dose of 250 mg/ kg of soft extract by intramuscular route for 15 days. Extract was fractionated in 45 cm column chromatography with a 2.5 cm diameter, containing G-60 silica gel, and 70-230 mesh (Sigma-Aldrich®). Nine fractions were obtained and assessed on macrophages infected with Leishmania sp to determine the active fraction and isolate the active compound, by separation, purification, and crystallization, analyzed by nuclear magnetic resonance (NMR) of 1H, 13C, and liquid chromatography coupled to mass spectroscopy (LC/ MS). Results. Fluid extract from the leaves of T. integrifolia presents leishmanicidal activity in M. auratus. Fraction F8 is active on infected macrophages at a dose of 14 μg/mL. An eudesman type sesquiterpene ((4aS, 5R, 6R, 8aR) -6-hydroxy-5, 8a-dimethyl-3- (1-methylethylidene) octahydronaphthalen-2 (1H) – one) was identified, by RMN 1 H, 13C, and LC / MS analysis. Conclusions. Fluid extract of leaves of Tessaria integrifolia Ruiz & Pav. presents leishmanicidal activity on Mesocricetus auratus with experimental leishmaniasis. Fraction F8 presents leishmanicidal activity on infected macrophages at a dose of 14 μg/mL. An eudesman type sesquiterpene was identified, according to 1 H, 13C, and LC / MS NMR analysis.